This invention relates to the field of disposable suction pumps for dispensing a liquid material, such as soap or alcohol detergent out of a container such as a bottle or the like. A vast number of different suction pumps have been proposed in the past. Generally, many suction pumps include a pressure chamber, from which a volume of liquid may be dispensed. The liquid leaving the chamber creates a negative pressure in the fluid chamber, which negative pressure functions to draw new liquid from the container into the pressure chamber, which thereby is filled and ready to dispense a new volume of liquid.
In use, the container is interconnected to the pump, and introduced in a dispenser, which is typically fixedly arranged on a wall in a bathroom or the like. Certain dispensers include a non-disposable pump which is integrated with the dispenser, and to which disposable containers may be coupled. In contrast, this invention relates to a disposable pump, which may be connected to a disposable container for attachment to a fixed (multiple use) dispenser.
One type of dispensers includes an actuation means for activating the pump and dispensing a volume of fluid. Another type of dispensers is arranged such that a portion of the pump extends out from the dispenser, displaying an actuation means arranged in integrity with the pump. There are generally two kinds of actuation means, whether integrated in the dispenser or in the pump.
One kind is a longitudinally acting actuation means. Longitudinally relates in this context to a direction parallel to the dispensing direction and to a spout of the pump. Pumps for longitudinal actuation often comprise a slidable piston which may be pushed/pulled in a longitudinal direction for diminishing/expanding the volume inside the pressure chamber of the pump, whereby the pumping effect is created. When the actuation means is formed in integrity with the pump it may comprise an outlet for dispensing the liquid.
Another kind of actuation means is a transversely acting actuation means. Transversely relates in this context to a direction transverse to the dispensing direction and to a spout of the pump. Pumps for transversal actuation are typically to be arranged in a fixed dispenser which comprises a transversally acting actuation means. The transversally acting actuation means may be a bar or the like, which upon transversal displacement acts to diminish the volume inside the pressure chamber of the pump.
As the pumps, containers are known in a large variety of forms. One particular type of containers are collapsible containers, which are intended to gradually collapse, decreasing their inner volume, as fluid is dispensed therefrom. Collapsible containers are particularly advantageous in view of hygienic considerations, as the integrity of the container is maintained throughout the emptying process, which ensures that no contaminants are introduced thereto, and that any tampering with the content of the container is impossible without visibly damaging the container. Use of collapsible containers involves particular requirements to the pumps. In particular, the suction force created by the pump must be sufficient not only to dispense the liquid, but also to contract the container. Moreover, a negative pressure may be created in the container, striving to expand the container to its original shape. Hence, the pump must be able to overcome also the negative pressure.
One type of collapsible containers is simple bags, generally formed from some soft plastic material. Bags are generally relatively easy to collapse, and the bag walls would not strive to re-expand after collapse, hence the bag walls would not contribute to the any negative pressure in the bag.
Another type of collapsible containers is known from e.g. EP 0 072 783 A1 and DE 90 12 878 U1. This type of collapsible containers has at least one relatively rigid wall, towards which the collapse of the other, less rigid walls of the container will be directed. Hence, hereinafter, this type of container is referred to as a semi-rigid collapsible container. This type of collapsible containers is advantageous in that information may be printed on the rigid wall, such that the information remains clearly visible and undistorted regardless of the state of collapse of the container. Moreover, for some contents, containers having at least one relatively rigid wall may be preferable over bags. However, collapsible containers having at least one relatively rigid wall may require a greater suction force generated from the pump in order to overcome the negative pressure created in the container during emptying thereof, than the bags.
For disposable pumps, there is a general need that the pump should be relatively easy and economic to manufacture. Moreover, it is advantageous if the pump includes materials that may easily be recycled after disposal and even more advantageous if the pump may be recycled as a single unit without need of separating its parts after disposal.
EP 1 215 167 describes a disposable pump comprising four plastic parts, each being formed by extruding techniques. The first part forms a connector portion being provided with threads, to be screwed onto a bottle. From the connector portion, a spout extends, said spout ending with a perforated plate through which content from the bottle may pass. The first part also forms a stem, extending from the perforated plate. A second part is thread onto the stem, and form two membranes, arranged one after the other, to constitute the valves of the pump. A third extruded part form a pressure chamber, which is connected to the first part so that the stem is introduced into the chamber and the membranes come in sealing contact with the inner walls of the pressure chamber. Finally, a fourth extruded portion made from an elastic material is connected to the outer wall of the pressure chamber, and in fluid contact therewith. The fourth extruded portion form a pressure bulb which, when depressed, increases the pressure in the pressure chamber.
The pump of EP 1 215 167 includes four parts which may be made of similar, however not identical materials. However, the pump of EP 1 215 167 would not be able to generate a suction pressure sufficient to empty a collapsible container, as the negative pressure from the collapsible container would inhibit the pressure bulb from expanding, and hence the function of the pump would be severely impaired if used with a collapsible container.
EP 0 854 685 describes another disposable pump. This pump is formed from two unitary elements both made entirely from plastic so as to be disposable as a unit. The two elements is a chamber forming body and a piston comprising a stem and two one-way valves. The piston is slidably received in the chamber forming body and liquid is drawn from the container by outward and inward movement of the piston in the chamber forming body. In the application, it is explained that if a positive pressure is maintained inside the container to which the pump is attached, the pump will reciprocate, e.g. manually applied forces may be used to move the piston inwardly against the pressure in the container, and the pressure in the container will urge the regulator outwardly in a return stroke.
From the above description, it is understood that if a negative pressure (a negative pressure) is maintained inside the container, as would be the case using a collapsible container, the piston will not be able to automatically return, which means that the feeding of liquid from the pump is relatively complicated.
Hence, none of the above-mentioned pumps are satisfactory for use with a collapsible container. Instead, known pumps that are used for collapsible containers are relatively expensive, including a relatively large number of components and often a great variety of materials.
In view of the above, there is a need for a disposable pump which may easily be recycled, and which is suitable for use with a collapsible container, in particular with a container of the semi-rigid type. Preferably, the pump should be returning such that no outside force must be applied to return the pump to a filled state after dispensing liquid.
Advantageously, the pump should be suitable for pumping liquid materials of different viscosities, from low viscosity material such as alcohol to high viscosity material such as liquid soap.
Preferably, the pump should be possible to activate using transverse activation means.
Preferably, the pump shall be resistant against leakage. Advantageously, the pump shall incorporate a suck-back mechanism to further protect against leakage.
The object of this invention is to provide a pump which fulfils one or more of the above-mentioned requirements.